Hitch device



Feb. 14, 1961 w. H. DU SHANE HITCH DEVICE 5 Sheets-Sheet 1 OriginalFiled March 26, 1953 INVENTOR. WALLACE H. DU SHANE ,,,g fi/w TORNEYSFeb. 14, 1961 w. H. DU SHANE HITCH DEVICE Original Filed March 26, 19535 Sheets-Sheet 2 Feb. 14, 1961 w. H. DU SHANE 2,971,589

HITCH DEVICE Original Filed March 26, 1953 5 Sheets-Sheet 3 INVENTOR.

WALLACE H. DU SHANE ORNEYS Feb. 14, 1961 w. H. DU SHANE 2,971,589

HITCH DEVICE Original Filed March 26, 1953 5 Sheets-Sheet 4 FIG. ll

FIG. l2

INVENTOR.

WALLACE H. DU SHANE ORNEYS Feb. 14, 1961 w. H. DU SHANE 2,971,589

HITCH DEVICE;

Original Filed March 26, 1953 5 Sheets-Sheet 5 FIG. l3

FIG. l4

INVENTOR. WALLACE H. DU SHANE T ORNEYS United States Patent HITCH DEVICEWallace H. Du Shane, Waterloo, Iowa, assignor, by

mesne assignments, to Deere & Company, a corporation of DelawareContinuation of abandoned application Ser. No. 344,865, Mar. 26, 1953.This application Mar. 1, 1957, Ser. No. 643,262

27 Claims. (Cl. 172-239) This application'is a continuation of mycopending application, Serial No. 344,865, filed March 26, 1953 forHitch Device, now abandoned.

The present invention relates generally to agricultural implements andmore particularly to tractor-carried and tractor-propelled impementscarrying one or more ground-working tools or the like.

The object and general nature of the present invention is the provisionof an implement hitch and control means particularly adapted for usewith tractors and implements having three-point connection draft links,which includes upper and lower link means and suitabe control mechanismand draft-transmitting means whereby the groundengaging tool means ismore or less freely movable in a generally vertical direction about avirtual hitch point or center of rotation, relative to the tractor, thatlies generally adjacent the rear axle of the tractor, whereby inoperation over uneven ground, such as over ridges, through swales andthe like, the implement remains generally parallel to the groundsurface, and it is a further object of this invention to provide meanswhereby the implement may be raised and lowered, as into and out of atransport position, by means providing for a movement of the implementgenerally about a virtual hitch point or center of rotation that lieswell forward relative to the tractor.

Still further, a feature of the present invention is the provision of ahitch device of the general character mentioned above, so constructedand arranged that the implement may be raised or lowered for operatingat different depths, with means associated with the draft linkagewhereby the greater the depth of operation the farther forward relativeto the tractor the virtual hitch point or center of rotation of theimp'ement is disposed.

An additional feature of this invention is the provision of means foradjusting the draft linkage control mechanism so as to provide theproper line of draft for various kinds of implements, some of which mayrequire a low line of draft for proper operation while others mayrequire a relatively high hitch point.

A further feature of this invention is the provision of hitch meansespecially constructed and arranged to provide for a low line of draftwhen the tool or toos enter the ground, and a further feature of thisinvention in this connection is the provision of means interconnectedwith the tractor power lift for changing the virtual hitch point whenthe tool means is, for example, shifted from its working position intoits lifted or transport position.

These and other objects and advantages of the present invention will beapparent to those skilled in the art after a consideration of thefollowing detailed description, taken in conjunction with theaccompanying drawings, in which:

Figure 1 is a side view of an impement and hitch mechanism in which theprinciples of the present invention have been incorporated, thepropelling tractor being shown only fragmentarily and the implementbeing illustrated as a two-bottom plow in normal operation.

Figure 2 is a view similar to Figure 1, showing the Patented Feb. 14,1961 positions and relations of the parts when the implement is fullyraised into a transport position.

Figure 3 is an enlarged fragmentary view of the cam mechanism andassociated parts for varying the effective or virtual hitch point of theimplement connection with the tractor, and also the line of draft, inaccordance with changes in the depth of operation.

Figure 4 is a top or plan view of the mechanism shown in Figure 3.

Figure 5 is a sectional view taken along the line 5--5 of Figure 4.

Figure 6 is a fragmentary sectional view taken along the line 6-6 ofFigure 1.

Figure 7 is a fragmentary plan view taken generally along the line 7--7of Figure l.

Figure 8 is a view similar to Figure 1, showing a modified form ofconstruction having certain advantages over the construction shown inFigure 1.

Figure 9 is an enlarged fragmentary view showing the details of the lineof draft and virtual hitch point adjusting mechanism incorporated in theimplement shown in Fig. 8.

Figure 10 is a top or plan view of the mechanism shown in Figure 7.

Figure 11 is a view somewhat similar to Figure 1, show-1 ing ahydraulically operated automatic depth control for the hitch mechanismdisclosed in Figure 1.

Figure 12 is an enlarged view of the ram-controlling va ve means.

Figure 13 is a fragmentary view showing the parts of the hydraulicmechanism in the positions they occupy when the implement is raised.

Figure 14 is similar to Figure in the lowered position.

Referring first to Figure 1, the present invention has been shown asincorporated in a tractor and two plow outfit. The tractor is indicatedin its entirety by the refer; ence numeral 20 and includes arelatively'narrow body supporting a power plant of any suitable type,the latter acting through transmission means to drive rear tractionwheels 23 that are supported on the laterally outer ends of axle shafts24. The power plant also is connected to actuate a power lift mechanism25 that includes, among other things, a transverse rockshaft 26 andmeans including a valve lever 27 for manually operating the power liftto rock the shaft 26 in one direction or the other by power. The powerlift shaft is arranged to move through two ranges, one being adepth-contro ling range and the other being a lifting range, therockshaft or power lift operated member 26 being adapted to be held inany se lected position within the lifting range and, when it is desiredto lift the implement into a transport position, the rockshaft 26 isrocked into and/or through its lifting range.

The implement is indicated in its entirety by the reference numeral 30and comprises ground-working tool means in the form of two moldboardplow bottoms 31 connected in any suitable way to a frame or beamstructure 32. The forward portion of the frame or beam structure carriesan upwardly extending mast section 33 providing an upper connectingpoint 34 and two lower laterally spaced apart connection points 35 towhich upper and lower link means 37 and 38 are adapted to be swingablyconnected. The upper and lower connection points 34 and 35 are formed toinclude ball-type connectors whereby the implement and the links 37 and38 may swing generally laterally relative to the tractor 20. The links37 and 38 and the implement 31 may also be swung generally verticallyrelative to the tractor. The forward end portion 39 of each of the lowerlinks 38 is connected through a bracket member 41 with the lower portionof the tractor. Preferably, each bracket member 41 is bolted 13, showingthe parts beat 42, to the drawbarsupport 43 that forms a part of thetractor 20. Each bracket41 is provided with side sections 44 and 45 thatare spaced apart angularly at their lower portions and convergeupwardly, as at 47 and 48, respectively, thereby providing an upwardlynarrowing space 49 receiving the forward'end 39 of the associated draftlink 38. The brackets 41 are arranged in this way so that, when thelinks 38 are in their lowered or operating position, as in Figures 1 and6, they are permitted to move laterally through a considerable angle,but when the links are in'an upper position, as in Figure 2, whichoccurs when the implement is raised into its transport position, thelateral swinging of the lower links 38 is limited. In this way, duringtransport, the implement 30 is held against lateral displacement.

Each of the brackets 41 is extended upwardly, as at 51, and apertured toreceive a pivot 52 on whichan associated bell crank member 53 isswingably mounted for movement about a generally transverse axis. Theupper arm of each of the two bell cranks 53 is apertured to receive anassociated pivot member 54 that forms a part of a cross-shaft structure55 not only the two pivot members 54, but also upper and lowerreenforciug plates 56 and 57 securely fixed, as by rivets 58, to theinner ends of the pivot members 54, and a vertical removable pivotmember that serves as a pivot connection receivin the forward end of theupper link means 37, the latter thus being swingable laterally relativeto the crossbar structure 55. The rear end of the upper link means 37 isprovided with a quick-detachable hook member 62 by which the rear end ofthe link member 37 may be connected with the ball connector at the upperattachment point 34 on the implement frame.

Secured to each end of the power lift rockshaft 26 is a lift lever 66that includes a pair of lever arms 67 and 63 and .a central hub section69 that is splined or otherwise constructed and arranged to be edrigidly to the rockshaft '26. Each of the lever arms 67 and 68 isprovided with a plurality of openings 71, 72, 73, and 74, these openingsin the two lever arms being disposed in transverse alinement,respectively. A fulcrum pin 75 is dispos'able in any of the pairs ofalined openings and rockably receives a lever 77 that is disposed at anintermediate point between the lift arms 67 and 68. The lever 77 isextended forwardly, as at 78, underneath the hub 69 and is'pivotallyconnected, as at 8 1, to a generally vertically (Fig. 7). The latterincludes,

extending link 82 thatis'pivotally connected at its lower end, as at 83,to the forward armfi of the associated bell crank 53. Each lever 77 isprovided with a generally longitudinally extending slot 35 that receivesthe associated fulcrum pin 75, and the rear end of each lever 77 isconnected by a generally vertically disposed link member 86 with thelower draft link 38 at that side of the implement. Preferably, the rearend of each of the levers 77 is bifurcated, as at 87, and apertured toreceive a pivot 88 that extends through a ball connector or the likecarried at the upper end of the associated lifting link 86. Either orboth of the lifting links 86 may be made longitudinally adjustable, andlikewise the upper link means 37 may be made longitudinally adjustableby any suitable means. The two levers 77 are rigidly connected togetherby a torsion bar 89, and by virtue of this construction, the two levers77, one at each side of the tractor, are constrained to move togetherand to act as one part. Each lever 77, with the associated link 82 andbell crank 53, constitutes motion transmitting means connecting thepower operated lift lever 66 with the lift link 86 and upper link means37 differentially, whereby for example, for a given movement of thepower lift arm 66 the links 37 and 86 may move ditferently.

At each side of the tractor, the power lift housing, indicated at 25a inFig. 4, carries a cam section 93 rigidly secured thereto in any suitablemanner. The cam section 93 is provided with a first cam slot 94 that isarcuate about the axis of the rockshaft 26, and'a secondcam slot 95 thatis shaped as best shown in Figure 3. The slots 94 95 are interconnectedand receive a pin 97 that is carried on an arm 93 rigidly fixed to andforming a part of the associated lever 77. Thus, as the power lift arm66 is raised and lowered, as by operation of the rockshaftZfi, the pin97, moving in the slots 3% and 95, acts to shift the associated lever"77' bodily relative to the associated fulcrum' pin 75. Thus, as thelift arms 66 move through their depth-adjusting range, the pins '97,sliding in the lower cam slots 95, serve to shift the arms 77 relativeto the associated fulcrum pins 95. This constitutes ratio changingmeans, since changing the position of the lever 77 relative to thefulcrum pin 75, changes the ratio of movement of one end of the lever 77relative to the corresponding movement'of the other end. However, whenthe power lift arms 66 move through their transport range, asrepresented by the arcuate slots M, at whici time the outer ends of thelift arms 66 engage the stops 99carried by the levers 77, the lattermove bodily with the lift arms 66 through the lifting range of thetractor power lift mechanism.

The operation of the present invention as so far described issubstantially as follows. Figure 1 shows the implement, a two-bottominoldboard plow, in a normal operating position, plowing about eightinches deep. For implements of this kind, the fulcrum pins are placed inthe lift arm openings 72 for average soil conditions. As the outfittravels over the ground surface, the plow 30 is free to float up ordown, relative to the tractor and the arms 66, to accommodate anyunevenness of the ground surface, as indicated in dotted and brokenlines in Figure I.

Upward movement of the plow relative to the tractor, as about the centerVC (Figure 1), will permit an upwardly directed movement of thelift'links 86, rotating the levers 77 clockwise about the fulcrum pins75. This allows the links 82 to move downward, permitting the bellcranks 53 to rotate in a clockwise direction, the upper link means 37tomove forwardly, and the imple ment 3% to tilt forwardly. This tips thepoints of the plow bottoms downwardly and acts to increase the sue tionof the plow bottoms and to cause the same either to increase the depthof operation, if the aforesaid upward movement of the implement werecaused by some means other than ground irregularities, or to tend tocause the plows to follow generally parallel to the surface of theground when the tractor passes through a swale or the like. On the otherhand, if the implement 31 should swing downwardly relative to thetractor, the levers 77 will swing in a counterclockwise direction, asviewed in Fig. 1, about the fulcrum pins 75, and .this will exert anupwardly directed pull through the links 32 against the forwardlyextending bell crank arms 74, swinging the bell cranks 53 in acounterclockwise direction and moving the upper link means 37rearwardly, thus tipping the plow upwardly. In this way, the depth ofplowing is de creased if the aforesaid downward movement were caused,not by ground irregularities, but by some other factor, such as theimplement striking a soft spot in the ground, or the like. On the otherhand, if the downward movement of the implement relative to the tractorwere due to the latter passing over the top of a ridge or the like, theplow would be tilted in a direction to maintain the same generallyparallel to the ground surface as the plow approaches the top of theridge. It will be noted from Figure 1, that in the up-anddown swingingof the implement. relative to the tractor discussed above, the implementmay be considered as moving about a virtual center of rotation or avirtual hitch. point VC that lies fairly close to the rear axle of thetractor, which permits the implement to remain nearly parallel to theground as the outfit passes over rolling land or the like.

Changing the fulcrum pins '75 from the holes 72 to some other holes, asto the ho1es. 71, 73, or 7.4, in the lift arms 66 provides differentratios of motion transr'nission between the lower links 38 to the upperlinks 37- through the bell cranks 53 and associated parts. example,placing the fulcrum pins in the forward holes 71 of the lift arms 66provides, during normal operation, a virtual center of rotation locatedrelative to the tractor at the point VC which, it will be noted, liessubstantially forwardly of the hitch point VC that is provided when thefulcrum pins 75 are disposed in the openings 72. When the pins 75 aredisposed in the openings 73, the virtual center of rotation VC islocated about as indicated in Figure 1, generally rearwardly of thecenter VC and when the pins 75 are disposed in the openings 74, thevirtual center of rotation VC is located, as shown in Figure 1,generally rearwardly of the center V.

The holes 71, 72 and 73 will be used for the majority of such implementsas moldboard plows, disk plows, disk harrows, bedders and the like, theforwardmost holes 71 being used for hard soil conditions and the holes73 being used for relatively light soils. The holes 74 provide thehighest line of draft and are used for shallow-operating implements,such as rear cultivators or the like.

During operation with the fulcrum pins 75 in position in the selectedholes 71-74, as required by the particular implement, soil conditions,or both, the pitch or suction of the implement can be adjusted bymovement of the rock-shaft 26 from one position to the other within itsdepth-adjusting range. For example, looking first at Figure 1, if itshould be desired to increase the suction of the implement, this can beaccomplished by operating the rockshaft 26 in a counterc ockwisedirection, as. viewed in Figure 1, the corresponding movement of thelift arms 66 in a downward direction permitting the levers 77 to movedownwardly. The forward ends 78 move immediately downwardly, since therear ends cannot at once move downwardly, because the implement cannotbe forced bodily downwardly into the ground. The downward movement ofthe front ends of the levers 77 act to swing the bell cranks 53 in aclockwise direction (Fig. 1). resulting immediately in a forward ordownward tilting of the im lement and an increase in the suction of thetools. This will result in the tools moving downwardly without delay toan increased depth of operation. Raising the power lift arms 66 willhave the opposite result, tipping the implement upwardly and decreasingthe suction of the tools. Furthermore, according to the principles ofthe present invention, the aforesaid upward or downward movement of thepower lift arms 66 serves, in addition to varying the suction of thetools, to change the position of the virtual hitch point or center ofrotation. This occurs because, for example, as the lift a ms 66 movedownwardly. the pins 97, guided by the stationary slots 95 on thetractor, serve to shift the levers 77 bodily in a generally fore-and-aftdirection relative to the associated fulcrum pins 75, thereby changingthe proportion of fore-and-aft movement transmtted by the bell cranks 53and associated parts to the upper link means 37 by a given amount ofvertical swinging of the lower links 38. For example, with the pins 75in the holes 72, if the depth of operation isincreased from eight inchesto ten inches, the virtual hitch point or center of rotation moves fromVC to VC and if the depth of operation is decreased to about six inches,for example, the virtual hitch point or center of rotation moves from VCto VC In other words, as the lift arms 66 are lowered to provide for anincreased depth of operation the resulting rearward movement of thelevers 77 causes a generally forward shift of the virtual center ofrotation of the implement, and when the power lift arms 66 are raised toprovide a more shallow depth of operation, the virtual center ofrotation is shifted generally rearwardly.

When it is desired to raise the tool into a transport position from anyoperating position, such as the one indicated by way of example, inFigure l, the operator actuates the power lift mechanism of the tractorand causes the rockshaft 26 to be rocked in a clockwise For direction,raising the lift arms 66 into their lifting range.- cam slots 94, theouter or rear ends of the lift arms came slots 94, the outer or rearends of the lift arms 65 come up against the stops 99. After contact isestablished, the levers 77 then move bodily with the lift arms and nolonger function as levers. However, the initial movement of the liftarms 66 toward their lifted position first causes the front ends of thelevers 77 to be elevated, which acts through the bell cranks 53 to shiftthe upper link means 37 rearwardly and tip or tilt the implementrearwardly, causing the points of the plow bottoms to be angledupwardly. This facilitates the emergence of the tools from the ground.By the time the arms 66 engage the stops 99, further lifting movementapplied to the implement 30 through the arms 66 raises the implement 36generally bodily about a forward virtual hitch point and more or less inparallel positions, this hitch point lying well forward on the tractor,as at the point of convergence of the lines of the links 37 and 38extended, because the levers 77 no longer pivot on their pins 75, andthe movement of the points or pivots 81 during the raising action merelycarries these points or pivots under the rockshaft 26, thereby causingvery little movement of the bell cranks 53. The raising moveroent of theimplement takes place generally about a virtual hitch point Where thefore-and-aft extending lines of the upper and lower links 37 and 38intersect. Thus, the raising of the implement is effected withoutexcessive power requirements, particularly since the rear end of theimplement is not raised very much higher than the rout end. Thisprovides a nearly parallel action during the lifting range of the powerlift, whereby heavier implements may be lifted easier than in priorconstructions with which I am familiar.

Generally speaking, the hitch mechanism and associated parts describedabove and shown in Figures 1-7 provide means whereby during normaloperation the virtual center of rotation or virtual hitch point of theimplement is located at the rear of the tractor and substantiallyunderneath the rear axle thereof. The advantage of this arrangement isthat the implement remains substantially at all times generally parallelto the surface of the ground when passing over rolling land. However,when the implement is to be lifted, the virtual hitch point is shiftedto a point well forward on the tractor, with the result that a nearlyparallel lift is provided. In this way, the heavier implements may belifted readily because the rear and need not be lifted as high as wouldbe the case if they were lifted about some virtual center of rotationadjacent the rear axle of the tractor.

In some cases, the implement may require an extremely loW line of draft,and in such cases the link 82. may be disconnected at the upper pin 31and the pin 81 inserted in a pair of holes 101 and 102 formed,respectively, in the bracket 41 and the adjacent portion of the bellcrank 53. This locks the bell crank 53 against rotation, and as a resultthereof, the virtual center of rotation lies gen erally at the pointwhere the fore-and-aft extending lines of the upper and lower links 37.and 38 intersect, which is well toward the front of the tractor. Whenthe parts are arranged in this way, the implement, in effect, floatsgenerally vertically until the stop 99 comes into contact with theassociated lifting arm 66, or until the latter is operated in theraising direction and contacts the stop 99 to raise the implement into atransport position. 7

A modified form of the present invention is shown in Figures 8-10. Inthis form of the invention certain sim-1 plifications have been made inthe line-of-draft adjusting levers 77, and the necessity fordisconnecting the link 82 from the associated lever 77 and locking thebell crank 53 in position has been eliminated.

Referring now to Figures 8-10, parts that are ide'n tical, orsubstantially so, with the parts described above have, been indicated bythe same reference numerals. Secured to each. end of the powerlift'rockshaft 26 isla 1 lifting arm 111 that 'is provided with a hubsection 112 splinedto the associated end of the shaft 26 and an armsection 113 having five openings 1 119, each adapted to receive a pivotpin 121 that is adapted to extend through a slot 122 formed in theassociated lever 123. Like the form of the arm 77 described above, thearm 111 is bifurcated, providing two sections 113 and pairs of openings115+119, the lever 123 extending between the lift arm sections 113. Therear or outer ends of the levers 123 are apertured to receive a torsionbar 125 that rigidly interconnects the two levers 123. The upper end ofthe associated lifting link 86 is pivotally connected, as at 126, withthe rear or bifurcated end of the lever 123. A stop 127 is formed oneach of the levers 123, and fixed to the innermost section 113 of thelifting arm 111 is a bracket 128 carrying a fixed pin 129 that isdisposed in the slot 94, 95 of the associated fixed car member 93. Theforward end of each of the levers 123 is pivotally connectechas at 131,to a generally vertical link 132 that, at its lower end, is connected bya pivot 133 to the forward arm of the associated bell crank 53.

In operation, the openings 116119 function substantially the same as theopenings 71-'74 described above. However, in this form of the invention,when the pin 121 is placed in the opening 115 with an end extending intothe slot 122, the lever 123 is locked to its associated lift arm 111.With the parts arranged in this way, very little movement is imparted tothe bell crank 53 by the front end of the lever 123, and therefore whenthe shaft '26 is rocked, the implement moves generally about a virtualcenter of rotation disposed well forwardly on the tractor.

The present invention as embodied in the construction illustrated inFigures 1-10 and described above provides, in effect, an implement hitcharrangement which maintains a substantially constant depth ofoperationwithout the use of any external source of power for forciblaising or lowering the implement. However, the hitch'constructiondescribed above is also especially adapted for use with an automaticcontrol mechanism which utilizes power from the tractor, such asproperly controlled fluid under pressure, as from a pump driven by thetractor engine, and one advantage of the present invention in thisconnection is the feature wherein an automatic control is made possiblethrough the use of the above described hitch linkage with anexternalsource of power, such as a hydraulic ram unit, in which the latter isnot called upon to actually lift the implement for the purpose ofdecreasing the draft ordropping the implement to increase the draft.Briefly, according to the present invention, means is provided,utilizing the above described hitch mechanism, whereby the hydraulicunit is provided, not for bodily raising or lowering the implement, butonly to change its line of draft and its suction, or angle of operationrelative to the ground surface. The hydraulic system of the presentinvention therefore requires considerably less power.

Referring now to Figure 11, secured to the rockshaft 26, preferablyinside the body or housing of the tractor, is an actuating arm 151 thatat its lower end is pivotally connected with a piston rod 152 that atits forward end abuts against a socket formed in a piston 153. Thelatter is disposed for sliding movement within a cylinder 154, thepiston and cylinder thus forming the principal parts of a ram unitindicated in its entirety by the reference numeral 155. The unit 155 issingle acting, and the piston 153 in operation moves toward and awayfrom the closed end of the cylinder 154. The closed end of the cylinderis indicated at 156. The flow of fluid to and from the cylinder 155 isunder the control of a valve unit indicated in its entirety by thereference numeral 58. The valve unit 158 includes a valve member 161disposed forsliding movement in a valve chamber 162, which latterchamber may be formed in the same member as the cylinas: 154, ifdesired- A bore or conduit 163 leads from 8 one end of the valve chamber162 into communication with the closed end 156 of the cylinder 154.

The valve member 161 is provided with'a pair of reduced sections 166 and167, and between these sections the valve member 161 is provided withenlarged cylindrh cal portions 162 and 169 thatare spaced'apart axiallyand are connected by tapering sections 171 and 172'a't their centralannular portion 173 in which a groove 174 is formed. A garter or detentspring 175 encircles and is lodge partly Within the groove 174 and isheld against lateral displacement with respect to the valve housing by"any suitable means, as by being disposed in an annular stationarychamber 176. At its forward end, the valve 7 member 161 extendsforwardly out of the housing in which the valve chamber 162 is formed,and at its other end the valve member 161 is provided with an elongatedstem section 181 of reduced diameter. A collar 132 is slidable on thisportion of the valve body, exteriorly of the housing and a relativelyheavy spring 183 is disposed between the collar 182 and the facingportion of an enlarged cylindrical valve section 185, the 'valve memberhaving tapered sections 186 and 187 at oppositesides of the cylindricalportion 185. The outer end of the valve chamber 162 is shown ascommunicating with a sump or the like, indicated somewhatdiagrammatically in Figure 11 by the reference character S. g

The valve chamber section 167a, formed by the reduced valve portion 167,communicates through the bore or passage 163 with the closed end of thecylinder 154. The passage 163 is connected by a bore or conduit 191 withthe chamber section 166a, formed by the reduced section 166 of the valvemember 161. In the normal or closed position of the valve member 161,the cylindrical section closes off the end of the conduit or passageway191. A third passage or bore 192 extends from the right end of the valvechamber 166a downwardly and outwardly to the sump S. A fourth conduitorpassage 194 extends from the generally central portion of the chamber166:: to a source of hydraulic pressure, such as a pump'P indicateddiagrammatically in the drawings as a constantrunning gear pump. Ahigh-pressure relief valve is shown at 195 for protecting the pump andthe associated fluid lines against abnormally high pressures. A fifthbore or passage 1%. which may register in diametrically oppositerelation with respect to the passage 192. e tends from the inner end ofthe valve chamber section 166a to a threeway v lve 1% that isincorporated in the passage or conduit 163.. in the position of thethree-way valve shown in Figure ll, the passage 196 is closed off andthe valve ch mber MM is subjected directlv to the pressure in the closedend 156 of the cylinder. 154. This provides automatic depth control, aswill be described below. The three-way valve 197 may be turned clockwise(Fi ure l i) so as to connect the line 196 with the line 163 be ow thethreerway valve. therebv isolating the valve unit from the pressure,within the cvlinder 154. This provides for position-responsive controlas pointed out below.

A hand controlled part in the form of .a lever 201 is mounted in asuitable location on the tra tor and is movable to d fferent positionsalong a sector 2152. A fulcrum link 2113 is connected at one end withthe hand lev r 261 and at the other end is connected by a pivot pin 204or the like to an intermediate oint on. a first servo link 2295. Theupper end f the link 295 is slotted and is connected to a ivot pin 266carried by the actuating arm 151 on the rocksbaft 26. The other end ofthe servo link 2955 is pivotally connected to trunnions 207 or the likeformed on t e collar 182 described above. A second collar 210 is firedrigidly to the outer end of the reducedtstem 181 of the valve member 161and pivotally receives, as through a s otted connection 211, the lowerend of a second servo link 212. The latter is connected 'by a short link213 with the pivot 284 at the rear endof the. fulcrum link 2%, saidpivotal connection including a pin 214 car.- riedby the link 212andaslot2l5forn1ed infihofl lt 2413 member 161 to the right. Thisrestrictively,

The upper end of the link 212 is pivoted directly to the actuating arm151, as at 216. A spring 217 is disposed between the collars 182 and210.

The operation of the form of the invention just described issubstantially as follows. Assuming that the implement and hitchstructure are in a normal operating position, such as is indicated infull lines in Figure 1, it will be noted that the compressive force inthe upper link 37, acting through the bell crank 53, will exert a pullthrough the link 82 against the forward end 78 of the lever 77. At thesame time, the downward reaction of the soil against the implement Wlllexert a tension through the lift links 86 against the rear ends of thearms 77. Thus, a downward load is imposed upon each of the lift arms 111which tends to rock the shaft 26 in a counterclockwise direction, andthis downward load or force is opposed by the pressure of the fluidwithin the closed end 156 of the cylinder 154. The pressure in this partof the ram is transmitted through the passageway 163 against theshouldered portion 169 on the inner end of the valve member 161, andthis force is counteracted by the force of the spring 183. The lattermay therefore be referred to as a draft spring since it is constructedand arranged to sustain normal draft forces, holding the valve member161 in its normal or neutral position, with the garter spring 173 lyingin the groove 174 and with the passages 192 and 194 in directcommunication with one another, whereby the oil from the pump P is freeto How through the valve chamber and back to the sump and reservoirwithout material restriction.

If for some reason the implement tends to go too deep, the forcetransmitted through the links 37, 86 and 132 will increase, thusincreasing the pressure in the closed end 156 of the cylinder 154. Thisincreased pressure acts against the shouldered portion 169 of the valvemember 161 and will force the latter outwardly. or rearwardly, againstthe action of the draft spring 183. This movement of the valve member161 closes the passage 192, whereby movement of oil to the reservoir orsump is terminated, and opens the passage 191 to the valve chambersection 166a, which receives oil under pressure from the pump throughthe line 194. However, the flow of oil from the latter through thechamber section 166a and the line 191 is restricted by virtue of thetapered section 187 of the valve member 161. Thus, the operation of thepump P moves the piston 153 at a relatively slow rate of movementoutwardly, thus rocking the shaft 26 in a clockwise direction, whichtilts the implement rearwardly and thus reduces its suction and raisesthe line of draft.

This provides, automatically, substantially the same action as isperformed by a manually controlled rocking of the shaft 26 (Figure 1) ina counterclockwise direction.

As the implement moves into a position of lesser depth, as a result ofthe action just mentioned, the draft decreases and the forcestransmitted by the links 37, 86

and 132 decreases, whereupon the pressure within the closedend 156 ofthe cylinder 154 decreases and the spring 183 returns the valve member161 to its normal or neutral position. Due, however, to the new positionof the actuating arm 151, carrying the pin 206 upon which the upper endof the link 205 is pivoted, the pressure within the system is slightlygreater than it was when the valve originally moved into a raisingposition; that is, the spring 183, at the time the valve 161 is returnedto its neutral position, is compressed to a slightly greater degree thanbefore. Thus, any tendency for the system to overcorrect for theabove-mentioned increase in draft is eliminated. This prevnts hunting ofthe controlling mechanism. 7

' If for some reason the implement tends to operate too shallow, thepressure in the closed end of the cylinder decreases, and as a resultthe spring 183 forces the valve through the tapered section 186, opensthe line 191' to the reservoir or sump S, and as a consequence thereofthe rockshaft 26 and lift arms 111 are permitted to rotate in acounterclockwise direction, and this increases the suction of theimplement and lowers the line of draft to the implement. As theimplement then goes deeper, the draft reaction causes an increase in thepressure of the closed end of the cylinder 154 which, acting against theshouldered section 169 of the valve 161 through the passageway 163, actsto return the valve member 161 to a neutral or closed position at apoint where the pressure in the cylinder 154 is slightly less than itwas when the valve originally moved to its lowering position. This, forthe same reason as mentioned above, serves to prevent hunting of thecontrolling mechanism. In this way, therefore, the link 205 andassociated parts constitutes a compensating mechanism that preventsovercontrolling of the hydraulic means.

When it is desired to raise the implement into its transport position,the hand lever 201 is raised into its uppermost position. This actsthrough the fulcrum link 203 to immediately swing the link 2115 in aclockwise direction with respect to its upper pivotal connection withthe actuating arm 151, the resulting movement of the outer or lower endof the link 205 acting to shift the valve member 161 to the left, movingthe cylindrical section and the tapered section 187 away from thepassage 191, at the same time causing the cylindrical section 168 toclose off the low pressure line 192. Thus, the full pump pressure isimmediately available to raise the implement into its transportposition. However, as the rockshaft 26 and the arms 111 and 151 reachtheir uppermost positions, the second servo link 212, the upper end ofwhich is moved rearwardly as the actuating arm 151 is moved rearwardly,acts positively to return the valve member 161 to its normal or closedposition, thus preventing any overtravel of the piston in the raisingdirection. This position of the parts is shown in Figure 13.

With the implement in its raised position, the outfit is easilytransported from field to field, and when it is next desired to operatethe implement, the hand lever 201 is swung downwardly into its loweredposition as against a depth-controlling adjustable stop 2% (Figure 13).At the beginning of the lowering action, the downward movement of thehand lever 2G1 acts first through the link 212 to move the valve member161 to the right,

0r forwardly, such a distance that the tapered portion 136 movesinwardly, or to the right, beyond the port 191. Thus, the implement islowered toward the ground at a fairly rapid rate since the passage 191is relatively unrestricted. This momentarily permits the implement tohave an increased angle of suction and low line of draft for quickentry. As the implement continues to lower, the actuating arm 151 actsthrough the link 212 to shift the valve member 161 rearwardly with apositive action. At the same time, the link 205 is swung in acounterclockwise direction so that at its lower end the latter actsagainst the spring 183 to establish a normal draftresisting force. Asthe implement reaches its normal operating position, the draft increasesand this acts through the passageway 163 against the valve member 161and restores the latter to a neutral or normal position, substantiallyas shown in Figure 11.

If it should be desired to eliminate the draft-responsive action, allthat it is necessary to do is to turn the threeway valve 197 into aposition cutting off the flow of fluid from the inner end of thecylinder through the passage 163 to the inner end of the valve member.Therefore, in this position of the valve 197, the system is no longercompensated by the draft, but the system is still responsive to theposition of the actuating arm 151, through the link 205.

. While I have shown and described above the preferred structure inwhich the principles of the present invention have been incorporated, itis to be understood that my invention is :not to' belimited to theparticular details, shown and described above, but that, in fact, widelydiffernt means may be employed in the practice of the broader aspects ofmy invention.

' What I claim, therefore, and desire Patent is:

1. 'In a mounted implement, 'the combination of a tractor having apower-operated member adapted to be moved to and held in differentselected positions, a ground-working means, including a frame, upper andlower, generally vertically swingable link means connected at their rearends with-said implement frame, a bell crank pivotally mounted on thetractor and having one arm pivotally connected with the forward end ofsaid upper link means, a lever pivotally connected at a mid-point withsaid power-operated member and swingable in generally oppositedirections about an axis at said midpoint relative to said poweroperated member when the latter is held in selected position, means atone side of said axis connecting one end of said lever with the lowerlink means, and means at the other side of said axis pivotallyconnecting the other end of said lever with the other arm of said bellcrank.

2. The invention set forth in claim 1, further characterized by meansconnected with said lever and said poweroperated member for changing thepoint of pivotal connection therebetween.

3. The inventionset forth in claim 1, further characterized by a pivotconnecting said lever and said poweroperated member, and means shiftablyconnecting said pivot with one of said lever and member.

4. The invention set forth in claim 3, further characterized by meansconnected with said power-operated member and actuated by movementthereof relative to the tractor for moving said shiftable pivot.

5. For use with a tractor of the type having a poweroperated lift memberand an implement of the type that is adapted to be connected with thetractor through upper and lower link means, with a lifting connectionacting against said lower link means: the improvement comprising a hitchdevice that includes motio. -transmitting means including a lever forconnecting said upper and lower link means whereby up and down swingingof the latter serves to shift said upper link means in a generallyfore-andaft direction, means providing a fulcrum for said lever on saidlift member, and means connected with said fulcrum means and the leverfor shifting one relative to the other in repsonse to movement of saidlift member relative to the tractor.

6. For use with a tractor of the type having a power operated liftmember and an implement of the type that is adapted to be connected withthe tractor through upper and lower link means, with a liftingconnection acting against said lower link means: the improvementcomprising a hitch device that includes motionrtransmitting meansincluding a bell crank adapted to be mounted on the tractor with one armconnected with the forward end of said upper link means, a lifting armadapted to be fixed to said power lift member, a lever, a pivot carriedby said arm and pivotally supporting said lever at a point between itsends on said arm for relatively free swinging movement, means connectingone end of said lever with the other arm of said bell crank, and meansfor connecting the other end of said lever with said lower link means.

7. The invention defined in claim 6, further characterized by fuicnimmeans carried by said lift arm, and means connected with said lever forshifting the latter relative to said fuicrum means by operation of saidpower lift member.

8. The invention set forth in claim 7, further characterized by saidlever shifting means comprising a cam adapted, to be fixed to thetractor and engageable with tosecure by Letters said'leverfor shiftingthe "latter relative to-said fulcrum means. a

9. For use with a tractor of the type having a poweroperated lift memberand an implement of the type that is adapted to'be connected with thetractor through upper and lower link means, with a lifting connectionacting against said lower link means: the improvement comprising a hitchdevice that includes motion-transmitting-means including a lever forconnecting said upper and lower link means whereby up-and-down swingingof the latterserves to shift said upper link means in a generallyfore-and-aft direction, means providing a fulcrum for said lever on saidtractor, and means connected with said fulcrum means and-the lever forshifting one relative to the other in response to movement of said liftmember relative to the tractor.

10. For use with a tractor of the type having a poweroperated liftmemberand an implement of the type that is adapted to be connected withthe tractor'through upper and lower link means, with a liftingconnection acting against said lower link means: the improvementcomprising a hitch device that includes motion-transmitting meansincluding a lever for connecting said upper and lower link means wherebyup-and-down swinging of the latter serves to shift'said upper'link meansin a generallyfore-and-aft direction, means providing a fulcrum forsaid-lever on said lift member, and means connected with said lever forshifting the fulcrum thereof relative to said lift .member for differentpositions of the latter.

11. In a mounted implement, the combination of a tractor having apower-operated member, a groundworking means, including a frame, upperand lower, generally vertically swingable link means connected at theirrear ends with said implement frame, a bell crank pivotally mounted onthe tractor and havingone arm pivotally connected with the forward endof said upper link means, a lever pivotally connected at'a mid-pointwith said power-operated member, means connecting one end of said leverwiththe lower link means, means pivotally connecting the other end ofsaid lever withthe other arm of said bell crank, one of said lastmentioned connecting means being detachable to permit interrupt-.ing'the'connection-between-the bell crank and said lever, and meansacting against the bell 'crank for limiting ,pivotaLmovement thereofrelative to the tractor.

12. The invention set forth in'claim 11, further characterizedaby stopmeans acting between said lever and said.powerroperated rnemher to limitthe movement of said lever relative thereto.

13. In a mounted implement, the combination of a tractor having-apower-operated member, a ground work- .ing means, including a frame,upper and lower, generally vertically swingable link means connected attheir rear ends with said implement frame, a bell crank pivotally.mounted on the tractor and having a generally vertically extending .armand agenerally fore-and-aft extending arm meanslpivotally connecting the.upper portion of said vertically extending arm with the forward end ofsaid upper link means, means connecting the outer end of the other-armwith saidpower-operated member, lift linkmeans connecting thepower-operated member with said lower linkmeans, whereby a forwardthrust exerted through the upper link means'against said bell crank istransmitted by the latter to the lift link means to apply a raisingforce to said lower link means, the meansconnectingthe bell crank withthe power-operated member including disconnectible parts, and meansfixing said bell crank to the tractor whensaid parts are disconnected.

14. A draft device for connecting an implement having upper and lowerconnection points with a tractor having a power-operated,implement-lifting and -adjusting member, said draft device comprisingupper'and lower linkmeans adapted to be pivotally connected at theirrear :ends with the implement connection points and.;at ;their;'forwardends with the vtractor,generally vertically acting liftingmeans'connected with said lower link means, motion-transmitting meanspivoted generally at an intermediate point on said power operated memberand connected at one end with said lifting means, means connecting theother end of said motion-transmitting means with said upper link means,whereby as said lower link means swings generally vertically said upperlink means is shifted generally fore-and-aft, and means connected withsaid motion transmitting means to shift the pivotal connection of thelatter relative to said power operated member so as to vary theproportion of movement of said lifting means relative to thecorresponding motion of said upper link means.

, 15. In a mounted implement, the combination of a tractor having apower-operated member, a ground-working means, including a frame, upperand lower, generally vertically swingable link means connected at theirrear ends with said implement frame, a bell crank pivotally mounted onthe tractor and having a generally vertically extending arm and agenerally fore-and-aft ex tending arm, means pivotally connecting theupper portion of said vertically extending arm with the forward portionof said upper link means, a lever of the first class connected at oneend with said lower link means and at its other end with said generallyfore-and-aft extending arm, and means connecting the fulcrum of saidlever with said power operated member.

16. In a mounted implement, the combination of a tractor having apower-operated member, a ground-working means including a frame, upperand lower, generally vertically swingable link means connected at theirrear ends with said implement frame, a bell crank pivotally mounted onthe tractor and having a generally Vertically extending arm and agenerally fore-and-aft extending arm, means pivotally connecting theupper portion of said vertically extending arm with the forward end ofsaid upper link means, motionreversing means carried by said poweroperated member and having generally op; positely. movable connectionsextending from said motion-reversing means to said lower link means andto the generally fore-and-aft extending arm of said bell crank,respectively, whereby a forward thrust exerted through the upper linkmeans against said bell crank is transmitted by the latter to the liftlink means to apply a raising to said lower link means. i

, 17. The combination with a tractor having a fore-andaft body supportedon a transverse rear axle and carrying a transverse lift rockshaft at alevel above said axle, and an "implement trailing the tractor, of hitchmeans connecting the implement to the tractor and comprising rearwardlyextending lift arm' means on the rockshaft, bell, crank meansseparatefrom the rockshaft and lift arm m'eans and'rockably mounted on thetractor on" a force transverse axis belowthe level of the tractor rearaxle,

said, bell crank means having first and second arm means, meansconnecting th e implement and the first arm means of the bell crankmeans for transmitting draft force at least in part to the bell crankmeans, generally upright force-transmitting means connecting the secondarm means of the bell crank means to the lift arm means for transferringsaid force at least in part to the lift arm means, and lift link meansconnecting the lift arm means and the implement for transferring alifting force to the implement.

18. The combination with a tractor having a power lift system thatincludes lift arm means and power means for raising said lift arm means,and a ground-fol owing implement, of hitch means to connect saidimplement with the tractor, comprising a pair of lower draft linksconnected at their rear ends to the implement and at their forward endsto the tractor, lift link means connecting said lift arm means with saiddraft links, upper link means connected at its rear end to an upperportion of the implement, a bell crank swingably mounted on the tractorand having a generally vertical arm pivoted to '14 t the forward portionof said upper link means and a generally horizontal arm connected withsaid liftarm means by disconnectable means, and means to lock said bellcrank to the tractor to prevent movement of the bell crankwhen saiddisconnectable means is disconnected.

19. In a mounted implement, the combination of a tractor having apower-operated member, a ground-working means, including a frame, upperand lower, generally vertically swingable link means connected at theirrear ends with said impelement frame, a bell crank pivotally mounted onthe tractor and having one arm pivotally connected with the forward endof said upper link means, a lever, means pivotally connecting the leverat a midpoint with said power-operated member so that the ends of saidlever move in opposite directions relative to said member, meansconnecting one end of said lever with the lower. link means, and meanspivotally connecting the other end of said lever with the other arm ofsaid bell crank, up and down swinging of said lower link meansresulting, respectively, in fore and aft tilting of said ground-workingmeans.

20. In a tractor mounted implement, the combination of a tractor havinga power-operated arm, a ground working means including a frame, draftreaction receiving means connected with said frame and with the tractorand including a first lever fulcrumed on the tractor and having twoparts, means connecting one of said parts with said frame, a secondlever, means pivotally supporting said second lever on said poweroperated arm for swinging movement about a point between the ends ofsaid second lever, whereby the latter is swingable relative to thetractor and said power-operated arm, said second lever having one endportion connected with the other part of said first lever, meansconnecting another portion of said second lever with said power-operatedarm and reacting against the latter to transmit a lifting force to saidframe, and means connecting the other end portion of the second leverwith said frame.

21. The combination with a tractor having a foreand-aft body supportedon a transverse rear axle and carrying a transverse lift rockshaft, andan implement trailing the tractor, of hitch means connecting the imple'ment to the tractor and comprising rearwardly extending lift arm meanson the rockshaft, bell crank means separate from the rockshaft and liftarm means and rockably mounted on the tractor for movement relativethereto abouta transverse axis, said bell crank means having first andsecond arm means, means connecting the implement and the first arm meansof the bell crank means for transmitting draft force at least in part tothe bell crank means, force-transmitting means connecting the second armmeans of the bell crank means to the lift arm means-for transferringsaid force at least in part to the lift arm means, and lift link meansconnecting the lift arm means and the implement for transferring alifting force to the implement.

22. In a tractor mounted implement, the combination of a tractor havinga power-operated arm, a ground working means including a frame, draftreaction receiving means connected with said frame and with the tractorand including a first lever fulcrumed on the tractor and having twoparts, means connecting one of said parts with said frame, and meansconnecting said power-operated arm with the other of said lever partsand with said frame, whereby draft reaction of the implement istransmitted through said power-operated arm to said frame as a liftingforce.

23. In a tractor mounted implement, the combination of a tractor havinga power-operated member, a ground working means including a frame,generally vertically swingable draft transmitting means connecting saidframe with the tractor, lift link means connecting said poweroperatedmember with said generally vertically swingable draft transmittingmeans, whereby movement of said power-operated member in one directionserves to raise said draft transmitting means and the implement. con:nected therewith, a bell -crank,means pivotally mounting thebell crankon the tractor,said bell crank being movable relative to the tractor andhaving a generally hori: zontal arm and a generally vertical arm, meansconnecting the latter arm with said frame so'as to receive the draftreaction thereof, and means connecting the generally horizontal bellcrank arm with said lift linkmeans and including means reacting againstsaid power-operated member, whereby the reaction of said implement draftis transmitted to said bell crank and acts against 'said power operatedmember and through said vertically swingable draft transmitting means toexert a lifting force on the implement. g

24. The combinationwith a tractor including a'power operated rockshaft,and an implement trailing the tractor, of hitch means connecting theimplement to the tractor,

' comprising lift arm means on the rockshaft, power means adapted to beextended and .retracted and to be held in selected positions, meansconnecting said power means with said lift arm means, lever meansseparate from the rockshaft and lift arm means and'rockably mounted onthe tractor, said lever means having firstand second movable portions,means connecting the implement and the first lever portion of said levermeans for transmitting draft reaction at least in part to said levermeans, forcetransmitting means extending upwardly from the second leverportion of said lever means to said lift arm means and thence downwardlyto the implement, said force transmitting means reacting against saidlift arm'means when the power means is held in selected position totransmit said draft reaction to the implement as a lifting force. 25. ina mounted implement, the combination of a tractor having apower-operated memberadapted to be held against movement, aground-working means including a frame, upper and lower, generallyvertically swingable link means connected at their rear ends With saidimplement frame, a bell crank pivotally mounted on the tractor andhaving a generally vertically extending arm and a generally fore-and-aftextending arm, said bell crank being freely movable relative to saidpower-operated member, means piovtally connecting the upper portion ofsaid vertically extending arm with the forward end of said upper linkmeans, lever means, pivot means mounting said lever means at anintermediate point for freely swingable movement on said power-operatedmember, means connecting the outerportion of the fore-and-aft extendingbell crank arm with one end of said swingable lever means, and lift linkmeans connecting the other end of said swingable lever means with saidlowerlink means, whereby a forward thrust exerted through the upper linkmeans against said bell crank is transmitted by the latter to the liftlink means through the swingable lever means reacting against poweroperated member, so as to' apply a raising force to said lower linkmeans.

26. The combination with a tractor having a fore-andaft bodv supportedon a transverse rear. axle and carrying a transverse lift rockshaft,"power means connected with the rockshaft and adapted optionally to rockthe latter and to hold the latter againstrocking, and'an implementtrailing the tractor, of .hitch means connecting the implement to thetractor and comprising rearwardly extending lift arm means on therockshaft, lever means separate from the rockshaft and lift arm meansand rockably mounted on the tractor, said lever means being mountedonthe tractor for movement relative to the rockshaft when the latter isheld by said power means in a given position relative to the tractor,said lever means having first and second arm means, means connecting theimplement and the first arm means of the lever means for transmittingdraft force at least in part to the lever means, force-transmittingmeans connecting the second arm means of the lever means to the lift armmeans for transferring said force at least in part to the lift armmeans, and lift link means contreating the liftarm rneans'and theimplement for transferring at least part of said draft force to' theimplement as a lifting force.

' 27. The combination with 'a tractor having a power operated rockshaftand an implement trailing the tractor, of hitch meansconnecting theimplement to the tractor and comprising lift arm means on the rockshaft,means connecting the lift arm-means with the implement, a first leverfulcrumed on the tractor and having two parts, means connecting one partof said'first lever with the implement so as to receive draft reactiontherefrom, a second lever, means supporting said second lever on thetractor whereby the second lever is swingable relative to the tractorand said lift arm means generally about a point between the ends of saidsecond lever, means connecting one end portion of said second lever withthe other part of said first lever so as to receive said draft reactiontransmitted thereto from said implement by said first lever, and meansconnecting another portion of said second lever with said lift arm meansand reacting against the latter and acting through the means connectingthe lift arm means with the implement to transmit a lifting force tosaid implement.

References Cited in the file of this patent UNITED STATES PATENTS155,707 Australia Mar. 16, 1954

